Form gage lean adapter

ABSTRACT

A turbine or compressor blade is held in an adapter for a guillotine gage for checking lean in any direction. The adapter includes a plurality of cylindrical forms which are slidingly intercoupled with keys and keyways on adjacent faces to permit relative movement along an X and a Y axis within the confines of a gap generated with respect to the stacking axis of the airfoil under test. The adapter is provided with a series of indicia markings equally spaced at 2* 30&#39;&#39; so that the adapter generates the aforementioned circle when adjusted to a predetermined lean tolerance. The gap is formed by parallel conically shaped surfaces, one of these surfaces on one of the cylindrical forms and the other on the inside of a threaded adjusting ring. The ring carries the indicia for which each of the markings of 2* 30&#39;&#39; is equal to 0.001 tolerance. Tolerance may therefore be directly set by appropriate adjustment of the ring.

United States Patent Mueller [451 Mar. 21, 1972 [54] FORM GAGE LEANADAPTER Primary Examiner-Leonard Forman Assistant Examiner-Dennis A.Dearing [72] lnventor. Charles L. Mueller, Harrisburg, Pa. Atmmey Hil1,Sherman, M e r 0 Hi Gross & Simpson [73] Assignee: TRW-Inc., Cleveland,Ohio [57] ABSTRACT 22 Filed: July 22, 1969 [2]] Appl. No.: 843,666

A turbine or compressor blade is held in an adapter for a guillotinegage for checking lean in any direction. The adapter includes aplurality of cylindrical forms which are slidingly intercoupled withkeys and keyways on adjacent faces to permit relative movement along anX and a Y axis within the confines of a gap generated with respect tothe stacking axis of the airfoil under test. The adapter is providedwith a series of indicia markings equally spaced at 2 30' so that theadapter generates the aforementioned circle when adjusted to apredetermined lean tolerance. The gap is formed by parallel conicallyshaped surfaces, one of these surfaces on one of the cylindrical formsand the other on the inside of a threaded adjusting ring. The ringcarries the indicia for which each of the markings of 2 30' is equal to0.001 tolerance. Tolerance may therefore be directly set by appropriateadjustment of the ring.

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sum u 0F 4 Cl 5 l I II I INVEN'I'OR. J25. j 5 I W495i. jfaggfr FORM GAGELEAN ADAPTER BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to apparatus for gaging airfoil-, and moreparticularly to apparatus for checking lean during durin the manufactureof airfoils.

2. Description of the Prior Art In the manufacture of turbine blades andcompressor blades, bar stock undergoes a number of qualification testsafter which it is forged and machined to the approximate dimensions andshape of the desired airfoil. The stock is first forged to provide aroot section at one end thereof and a blade portion at the other endthereof, after which a blocking operation is performed to develop theapproximate shape of the entire blade. The blade is then forged to shapeand machined into a finished product. In finishing a blade, a guillotinegage is employed for periodic checks of size to insure that dimensionsof a blade are accurate. As the leading and trailing edges of theairfoils are shaped, the airfoils are checked periodically with formtemplates to insure that the dimensions thereof are accurate.Heretofore, it has been necessary to take readings of lean deviations ofthe blades and relate these readings to a look up table to determinewhether the blades are within the lean tolerances. This required lookingfor a complimentary value on the table for every indicator reading.

It is highly desirable, and a primary object of the present invention,to obviate the necessity for a table of complimentary values byproviding form gage lean apparatus for direct reading in determinationof lean.

SUMMARY OF THE INVENTION According to the invention, a form gage leanadapter is provided for attachment to a guillotine gage whereby theguillotine gaging operations and form checking may be accomplished morereadily. The adapter comprises a plurality of cylindrical members whichslidingly engage one another, with two of the members being slidablealong an X axis and a Y axis, respectively, in accordance with adjacententer-engaging keys and keyways of these members. The cylindricalmembers are located with respect to one another and with respect to thestacking axis of an air foil under test. A screw adapter is secured tothe guillotine gage base portion and threadedly engages a calibrated nutcarrying indicia of calibration to clamp the cylindrical memberstogether at any selected tolerance reading. The

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to apparatus for gaging airfoil, and more particularly toapparatus for checking lean during during the manufacture of airfoils.

2. Description of the Prior Art In the manufacture of turbine blades andcompressor blades, bar stock undergoes a number of qualification testsafter which it is forged and machined to the approximate dimensions andshape of the desired airfoil. The stock is first forged to provide aroot section at one end thereof and a blade portion at the other endthereof, after which a blocking operation is performed to develop theapproximate shape of the entire blade. The blade is then forged to shapeand machined into a finished product. In finishing a blade, a guillotinegage is employed for periodic checks of size to insure that dimensionsof a blade are accurate. As the leading and trailing edges of theairfoils are shaped, the airfoils are checked periodically with formtemplates to insure that the dimensions thereof are accurate.Heretofore, it has been necessary to take readings of lean deviations ofthe blades and relate these readings to a look up table to determinewhether the blades are within the lean tolerances. This required lookingfor a complimentary value on the table for every indicator reading.

It is highly desirable, and a primary object of the present invention,to obviate the necessity for a table of complimentary values byproviding form gage lean apparatus for direct reading in determinationof lean.

SUMMARY OF THE INVENTION According to the invention, a form gage leanadapter is provided for attachment to a guillotine gage whereby theguillotine gaging operations and form checking may be accomplished morereadily. The adapter comprises a plurality of cylindrical members whichslidingly engage one another, with two of the members being slidablealong an X axis and a Y axis, respectively, in accordance with adjacententer-engaging keys and keyways of these members. The cylindricalmembers are located with respect to one another and with respect to thestacking axis of an air foil under test. A screw adapter is secured tothe guillotine gage base portion and threadedly engages a calibrated nutcarrying indicia of calibration to clamp the cylindrical memberstogether at any selected tolerance reading. The calibrated nut and oneof the cylindrical members have complimentary conically shaped surfaceswhich part selected distances upon rotation of the nut to selectivelygenerate annular boundaries concentric with the stacking axis andthereby select tolerances so that the cylindrical members are free tomove along the X and Y axis within the confines of the circular gapcreated between the conically shaped surfaces. The gap therefore definesthe permissable tolerance at any selected profile of a blade and theamount of permissable movement along the X and Y axes determines whetherthe blade is within tolerance.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesof the invention, its organization, construction and operation will bereadily apparent from the following description of a preferredembodiment thereof, taken in conjunction with the accompanying drawings,although variations, and modifications may be effected without departingfrom the spirit and scope of the novel concepts of the disclosure, andin which:

FIG. 1 is a pictorial representation of a guillotine gage having a formgage lean adapter mounted thereon according to the invention;

FIG. 2 is a cross-sectional elevational view of a form gage lean adapteraccording to the present invention;

FIG. 3 is an exploded view of a form gage lean adapter according to theinvention;

FIG. 4 is a top view of a form gage lean adapter according to theinvention; and

FIG. 5 is an elevational view of the form gage lean adapter of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, there isgenerally shown at 10 a guillotine gage 11 including a table portion 12and a plurality of guillotine blades 13, further referenced l3a-l3f,which are secured to a frame 14.

A lean adapter 15 is mounted on the table portion 12 of the gageapparatus and comprises a screw adapter 16 having a threaded outersurface 17. The screw adapter includes a groove 18 which extendsdiametrically across its upper face centrally of the Y axis of the gage.A pilot diameter 19 extends from the lower face of the screw adapter 16to locate the screw adapter within a bore 21 of the guillotine gageturret 20. A pair of screws 22, further referenced 22a and 22b, areprovided for securing the screw adapter 16 to the turret 20. The screws22a and 22b extend through corresponding holes 23a and 23b of screwadapter 16 and threadedly engage thread holes 23c and 23d, respectively,in the turret 20.

A cylindrical member 27 is slidably mounted on top of screw adapter 16with a key 30 which extends diametrically across its lower surface beingreceived by groove or keyway 18 of screw adapter 16. The cylindricalmember 27 includes a pair of indentions 28a and 28b in the peripherythereof for providing clearance for screws 22a and 22b. A pin 24 isreceived by a hole 25 in the screw adapter 16 and a hole 26 alignedwithin the guillotine turret 20 to properly index components 16 and 27and prevent rotation.

The cylindrical member 27 is provided with a groove or keyway 29 whichextends diametrically across the upper surface thereof and liescentrally of the X axis of the gage apparatus. The keyway 29 receives acooperable key 32 which extends diametrically across the undersurface ofa second cylindrical member 31 to provide a sliding engagement betweenthe cylindrical members along the X axis of the gage apparatus. Thesecond cylindrical member has a groove 33 formed in the top surfacethereof diametrically thereacross and centrally of the Y axis of theapparatus to permit the mounting of the blade holding apparatus 36 bymeans of a pair of screws 35a and 35b which threadedly engage threadedholes 340 and 34b of the second cylindrical member 31.

The second cylindrical member 31 includes an axial bore 37 therethroughhaving a conical section 38 for receiving a correspondingly shapedconical section 41 of a screw 40. Screw 40 includes a threaded shaft 42which extends through bore 37 and align bores 43 of the firstcylindrical members 27 and 44 of the screw adapter 16. A cylindricallyshaped compres-' sion spring 45 axially receives threaded shaft 42 andis secured between a bore 46 of screw adapter 16 and a groove 49 of anut 47 which has a threaded bore for receiving threaded shaft 42. A lockscrew 51 is also received by the threaded bore 48 for locking screw 40in place.

The axial bores 44, 43 and 37 of the screw adapter 16, first cylindricalmember 27 and second cylindrical member 31, respectively, are oversizedwith respect to the diameter of the shaft 42 to permit travel of thefirst and second cylindrical members along the X and Y axes of theapparatus.

A cylindrical nut 52 has an internal thread 53 for engaging the threads17 of the screw adapter 16. The cylindrical nut 52 also includes aninternal conical surface 54 which corresponds in shape to a conicalsurface 55 of the second cylindrical member 31. Lower portion of thecylindrical nut 52 is provided with a pair of slots 56a and 56b cutacross the diameter thereof to within approximately 1% inch of eachother at diametrically located positions 57a and 57b to provide a pairof spring portions 58a and 58b on opposite sides of the nut 52. Each ofthe spring portions 58a and 58b are provided with clearance holes 59aand 59b, respectively for receiving screws 60a and 60b, respectively.The screws 60a and 60b engage threaded bores 61a and 61b in the mainbody 62. Adjustment of these screws during assembly of the nut 52 to thescrew adapter 16 removes any possibility of thread backlash.

A cylindrical detent ring 63 is provided circumferentially about thecylindrical nut 52 and is secured thereto by means of a pair of screws65a and 65b which engage threaded bores 67a and 67b in the main body 62of the cylindrical nut 52 through access holes 66a and 66b,respectively. The cylindrical detent ring 63 includes a plurality ofdetents 64, further referenced 64a, 64b and 640 to provide properpositioning of the cylindrical nut 52 during assembly, when engaged witha detent pin 68. The detent pin 68 extends vertically through a bore 69in turret 20 and includes a head 70 which is located in a counterboreportion 71 of turret 20. The detent pin 68 is spring loaded by provisionof a compression spring 72 between the head 70 of the detent pin and aplug 73 which seals the counterbore 71 of the turret 20.

As shown in FIG. 1 (and as shown in phantom in FIG. 2), the apparatus isprovided with gripping jaws 74 and 75 which are movable relative oneanother by means of an adjusting knob 76 having a threaded adjustingshaft 77. The jaws 74 and 75 receive and clamp the root 79 of a blade 78therebetween with the blade centered with respect to the apparatus inaccordance with the stacking axis of the air foil 81. The blade 78 isfurther shown to include a shoulder portion which divides the bladeportion from the root portion at 80.

The form gage lean adapter is assembled by securing the screw adapter16, cylindrical member 27 and cylindrical member or mounting disc 31together with the screw 40, the

compression spring 45, the nut 47 and the lock screw 51. Screws 22a and22b are employed to secure the just-assembled members to the turret 20.The cylindrical nut 52 with the detent ring 63 assembled thereto isthreaded onto the aforementioned sub-assembly and adjusted for threadbacklash with screws 60a and 60b. The cylindrical nut is turned on itsthread 53 until the conical surface 54 thereof engages the conicalsurface 55 of the mounting disc 31, thus restricting travel of thecylindrical members in any direction. This is known as the basic closedposition.

Turning the cylindrical nut 52 counterclockwise until a premachineddetent 64 in detent ring 63 engages the detent pin 68 provides acircular gap between the conical surfaces 54 and 55, which gap isconcentric with the stacking axis of the airfoil. The mounting disc 31and the cylindrical member 27 are moved in directions along both the Xand Y axes by means of the keys and keyways provided, for exampleelements 29 and 32, over the distance of the circular gap generated inany direction from its original center without any rotation of the part.Therefore, the apparatus satisfies the part requirement of lean in anydirection.

The following illustrative example is given in order that the foregoingoperations may be best understood. The cylindrical nut 52 includes asurface which is provided with a series of indicia marks 82 equallyspaced-apart at, for example, 2 30'. Each'of 2 30' intervals is equal toa tolerance of 0.001 lean. Assuming that the part is permitted a lean of0.040 in any direction at section F-F and a lean of 0.030 in anydirection at section C-C, the detent ring 63 is rotated 40 marks fromthe basic position B to the detent mark F, since 0.001 lean equals 230'; the rotation is 40 X 2 30', or The part can now be moved along theX and Y axes in any direction between the confines of the gap generatedbetween conical surfaces 54 and 55 of the cylindrical screw 52 and themounting disc 31 to permit check of the form of the part at this sectionto a template. The detent ring 63 is then rotated to the detent marked C30 marks from the basic position B; whereat the rotation is 30 X 2 30,or 75. The part can now be moved along the X and Y axes in a directionwithin the confines of the new gap generated between the conicalsurfaces 54 and 55 to pennit checking of the form of the part to thetemplate at this section. Rotation of the detent ring 63 back to thebasic position B locks the part in the basic position to permit regularroutine guillotine gage functions to be performed.

Generally then there has been described a form gage lean adapter for aguillotine gage which permits direct checking of lean tolerance withrespect to the template at any desired section by merely selectivelyrotating a dial to set the permissable tolerance. The part under testmay then be moved along the X and Y axes of the apparatus in anydirection within the confines of a circular gap generated by setting ofthe dial, representing and being formed in accordance with thepermissable lean tolerance at the desired section of the airfoil undertest. Accordingly, the necessity of taking readings for lean deviationand looking up complimentary values thereof in a table is obviated.

What I claim is:

1. Apparatus for checking lean tolerance of an airfoil having a stackingaxis, comprising: first means for holding the airfoil; said first meansmounted for movement nonnal to the stacking axis for positioning theairfoil adjacent a form template; and second means associated with saidfirst means and operable to selectively generate annular boundaries withrespect to said first means, said boundaries concentric with thestacking axis and corresponding to lean tolerances at selected sectionsof the airfoil to limit movement of said first means and airfoil towardthe form template.

2. The apparatus according to claim 1, wherein said first meanscomprises a plurality of members which are slidably engaged with eachother for movement along respective axes normal to the stacking axis,one of said members including a first conically-shaped surface, and saidsecond means comprises a selectively adjustable member including asecond conically shaped surface disposed about and conforming to theshape of said first surface, said adjustable member being movablerelative said one member to generate an annular gap between said firstand second surfaces the width of which corresponds to a selected leantolerance.

3. The apparatus according to claim 1, wherein said first means includesmeans for moving the airfoil in any direction along X and Y axes normalto the stacking axis of the airfoil.

4. The apparatus according to claim 1, wherein said first meanscomprises a plurality of members, a first of said members being fixed, asecond member carried on said first member, a first key on one of saidfirst and second members and a corresponding first keyway in the otherof said members disposed for relative movement of the members along afirst axis normal to the stacking axis, a third member carried by saidsecond member, a second key on one of said second and third members anda corresponding second key way in the other of said second and thirdmembers disposed for relative movement of the second and third membersalong a second axis normal to the stacking axis of the airfoil andnormal to said first axis, said third member including a first conicallyshaped surface, and said second means comprises an adjustable membercoupled to said first member, said adjustable member including a secondconically shaped surface parallel to said first conically shapedsurface, said adjustable member movable relative said third member toprovide a gap of selected width between said two conically shapedsurfaces corresponding to the lean tolerance at a selected section ofthe airfoil.

5. Apparatus for restricting movement of a formed element relative aform template, comprising:

first means fixed with respect to the template,

second means mounted on said first means for reciprocal movement along afirst axis, third means mounted on said second means for reciprocalmovement along a second axis that is perpendicular to said first axis,said third means including means for holding the formed element, and

fourth means embracing said first, second and third means and includingmeans forming a boundary within which said second and third means arefree to move along said first and second axes respectively.

6. The apparatus set forth in claim 5, wherein said first, second andthird means are of substantially cylindrical shape and each include acentral bore therethrough, and said apparatus further comprisesfastening means including a shaft of lesser diameter than the diametersof said bores extending through said bores for securing said first,second and third means together while permitting relative movement alongsaid first and second axes.

7. The apparatus set forth in claim 6, wherein said bore of said thirdmeans includes a conically shaped surface and said fastening meansincludes a conically shaped surface conforming thereto.

8. The apparatus set forth in claim 6, wherein said fastening meansincludes means for engaging said shaft and spring means disposed betweensaid engaging means and said first means for urging said shaft toward apredetermined position.

9. The apparatus set forth in claim 6, wherein said fastening meanscomprises means for locking said shaft to prevent rotation thereof.

10. The apparatus set forth in claim 5, wherein said first means andsaid second means are slidably engaged, one of said means including akey protruding therefrom and the other of said means including a keywaytherein for receiving said key, said key and keyway lying along saidfirst axis.

11. The apparatus set forth in claim 5, wherein said second means andsaid third means are slidably engaged, one of said means including a keyprotruding therefrom and the other of said means including a keywaytherein for receiving said key, said key and keyway lying along saidsecond axis.

12. The apparatus set forth in claim 5, wherein said first meansincludes a first cylindrical threaded surface, said fourth meansincludes a second cylindrical threaded surface engaging said firstthreaded surface and rotatably adjustable relative thereto, said thirdand fourth means including respective parallel conical surfaces whichpart to a gap of selective width upon rotation of said fourth means, thegap defining the tolerance of said formed element and said parallelsurface of said fourth means defining said boundary.

13. The apparatus set forth in claim 12, wherein said fourth meansincludes an outer surface and spaced-apart indicia markings on saidouter surface corresponding to predetermined tolerances.

14. The apparatus set forth in claim 12, wherein said fourth meansincludes means for preventing thread backlash between the threads ofsaid first cylindrical surface and the threads of said secondcylindrical threaded surface.

15. The apparatus set forth in claim 12, wherein said fourth meansincludes an annular ring having at least one slot therein generallyperpendicular to the axis of rotation of said ring dividing said ringinto at least two portions one of which is movable with respect to theother and both of which carry said first cylindrical threaded surface,and means for moving said one portion with respect to the other portionto prevent thread backlash between said first and second cylindricalthreaded surfaces.

16. Apparatus for checking the form of an element against acorresponding template, said apparatus comprising:

a frame including a base and means for holding a form template;

first means secured to said base and fixed with respect to said formtemplate;

second means mounted for reciprocal movement on said first means along afirst axis;

third means mounted for reciprocal movement on said second means along asecond axis normal to said first axis and including means for holding aformed element, the movement of said second and third means along saidaxes permitting a form comparison of the element to the template in anydirection; and

fourth means for limiting movement of said second and third means, saidfourth means being adjustable to establish a boundary within which saidsecond and third means may move corresponding to a predeterminedtolerance between the formed element and the template.

17. Apparatus according to claim 16, wherein said fourth means isrotatably coupled to said first means, and comprising indicia forindicating predetermined tolerances corresponding to predeterminedangular positions of said fourth means.

18. Apparatus for checking the lean tolerance and form of a formedelement with respect to a corresponding form template, comprising framemeans including means for holding a form template and base means havingfirst and second bores therein,

a first disc-shaped member having an upper surface and a lower surface,a protrusion formed on its lower surface extending into said first bore,a third bore, a first keyway formed in its upper surface diametricallythereacross, and a threaded peripheral surface,

a pin disposed in said second and third bores to locate said firstdisc-shaped member relative said base,

a second disc-shaped member having an upper surface and a lower surface,a first key formed on its lower surface extending diametrically thereofand slidably disposed in said first keyway, and a second keyway formedin its upper surface perpendicular to said first key and first keyway toprovide first and second coordinate axes,

a third disc-shaped member having an upper surface and a lower surface,a second key formed diametrically across its lower surface and slidablydisposed in said second keyway, and a first conically shaped surface,

means mounted on said third disc-shaped member for holding a fonnedelement, the element being thereby movable toward the corresponding formin any direction as provided by said coordinate axes, and

a ring-shaped nut including inner threaded surface portion rotatablyengaging said threaded peripheral surface of said first disc-shapedmember, a second conically shaped inner surface portion parallel to saidfirst conically shaped surface of said third disc-shaped member, and anouter surface carrying spaced-apart indicia thereon corresponding topredetermined tolerance settings for rotation of said ring-shaped nut,said parallel surfaces parting an mount corresponding to a selectedtolerance upon rotary setting of said nut and said second UNITED STATESPATENT OFFICE CERTIFICATE CF CORRECTION Patent No. 3, 650, 035 DatedMarch 21, 1972 Inventor(s) Charles L. Mueller It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 1, line 5, read "airfoil-" as -airfoils-;

line 6, read only one "during"; Column 1, line 32 to Column 2, line 2 donot read the "SUMMARY OF THE INVENTION" or the "BACKGROUND OF THEINVENTIQN", a double recitation; V

Signed and sealed this 10th day of April 1973.

LS'EAL) Attest:

D ARD M. PLETCHER JR. ROBERT @OTTSCHALK it esting Officer Commissionerof Patents FORM PO-105O (10-69) USCOMM-DC 5O376-P69 U45. GOVERNMENTPRINTING OFFICE: I969 0-366-33

1. Apparatus for checking lean tolerance of an airfoil having a stackingaxis, comprising: first means for holding the airfoil, said first meansmounted for movement normal to the stacking axis for positioning theairfoil adjacent a form template; and second means associated with saidfirst means and operable to selectively generate annular boundaries withrespect to said first means, said boundaries concentric with thestacking axis and corresponding to lean tolerances at selected sectionsof the airfoil to limit movement of said first means and airfoil towardthe form template.
 2. The apparatus according to claim 1, wherein saidfirst means comprises a plurality of members which are slidably engagedwith each other for movement along respective axes normal to thestacking axis, one of said members including a first conically-shapedsurface, and said second means comprises a selectively adjustable memberincluding a second conically shaped surface disposed about andconforming to the shape of said first surface, said adjustable memberbeing movable relative said one member to generate an annular gapbetween said first and second surfaces the width of which corresponds toa selected lean tolerance.
 3. The apparatus according to claim 1,wherein said first means includes means for moving the airfoil in anydirection along X and Y axes normal to the stacking axis of the airfoil.4. The apparatus according to claim 1, wherein said first meanscomprises a plurality of members, a first of said members being fixed, asecond member carried on said first member, a first key on one of saidfirst and second members and a corresponding first keyway in the otherof said members disposed for relative movement of the members along afirst axis normal to the stacking axis, a third member carried by saidsecond member, a second key on one of said second and third members anda corresponding second key way in the other of said second and thirdmembers disposed for relative movement of the second and third membersalong a second axis normal to the stacking axis of the airfoil andnormal to said first axis, said third member including a first conicallyshaped surface, and said second means comprises an adjustable membercoupled to said first member, said adjustable member including a secondconically shaped surface parallel to said first conically shapedsurface, said adjustable member movable relative said third member toprovide a gap of selected width between said two conically shapedsurfaces corresponding to the lean tolerance at a selected section ofthe airfoil.
 5. Apparatus for restricting movement of a formed elementrelative a form template, comprising: first means fixed with respect tothe template, second means mounted on said first means for reciprOcalmovement along a first axis, third means mounted on said second meansfor reciprocal movement along a second axis that is perpendicular tosaid first axis, said third means including means for holding the formedelement, and fourth means embracing said first, second and third meansand including means forming a boundary within which said second andthird means are free to move along said first and second axesrespectively.
 6. The apparatus set forth in claim 5, wherein said first,second and third means are of substantially cylindrical shape and eachinclude a central bore therethrough, and said apparatus furthercomprises fastening means including a shaft of lesser diameter than thediameters of said bores extending through said bores for securing saidfirst, second and third means together while permitting relativemovement along said first and second axes.
 7. The apparatus set forth inclaim 6, wherein said bore of said third means includes a conicallyshaped surface and said fastening means includes a conically shapedsurface conforming thereto.
 8. The apparatus set forth in claim 6,wherein said fastening means includes means for engaging said shaft andspring means disposed between said engaging means and said first meansfor urging said shaft toward a predetermined position.
 9. The apparatusset forth in claim 6, wherein said fastening means comprises means forlocking said shaft to prevent rotation thereof.
 10. The apparatus setforth in claim 5, wherein said first means and said second means areslidably engaged, one of said means including a key protruding therefromand the other of said means including a keyway therein for receivingsaid key, said key and keyway lying along said first axis.
 11. Theapparatus set forth in claim 5, wherein said second means and said thirdmeans are slidably engaged, one of said means including a key protrudingtherefrom and the other of said means including a keyway therein forreceiving said key, said key and keyway lying along said second axis.12. The apparatus set forth in claim 5, wherein said first meansincludes a first cylindrical threaded surface, said fourth meansincludes a second cylindrical threaded surface engaging said firstthreaded surface and rotatably adjustable relative thereto, said thirdand fourth means including respective parallel conical surfaces whichpart to a gap of selective width upon rotation of said fourth means, thegap defining the tolerance of said formed element and said parallelsurface of said fourth means defining said boundary.
 13. The apparatusset forth in claim 12, wherein said fourth means includes an outersurface and spaced-apart indicia markings on said outer surfacecorresponding to predetermined tolerances.
 14. The apparatus set forthin claim 12, wherein said fourth means includes means for preventingthread backlash between the threads of said first cylindrical surfaceand the threads of said second cylindrical threaded surface.
 15. Theapparatus set forth in claim 12, wherein said fourth means includes anannular ring having at least one slot therein generally perpendicular tothe axis of rotation of said ring dividing said ring into at least twoportions one of which is movable with respect to the other and both ofwhich carry said first cylindrical threaded surface, and means formoving said one portion with respect to the other portion to preventthread backlash between said first and second cylindrical threadedsurfaces.
 16. Apparatus for checking the form of an element against acorresponding template, said apparatus comprising: a frame including abase and means for holding a form template; first means secured to saidbase and fixed with respect to said form template; second means mountedfor reciprocal movement on said first means along a first axis; thirdmeans mounted for reciprocal movement on said second means along asecond axis normal to said first axis and including means for holding aformed element, The movement of said second and third means along saidaxes permitting a form comparison of the element to the template in anydirection; and fourth means for limiting movement of said second andthird means, said fourth means being adjustable to establish a boundarywithin which said second and third means may move corresponding to apredetermined tolerance between the formed element and the template. 17.Apparatus according to claim 16, wherein said fourth means is rotatablycoupled to said first means, and comprising indicia for indicatingpredetermined tolerances corresponding to predetermined angularpositions of said fourth means.
 18. Apparatus for checking the leantolerance and form of a formed element with respect to a correspondingform template, comprising frame means including means for holding a formtemplate and base means having first and second bores therein, a firstdisc-shaped member having an upper surface and a lower surface, aprotrusion formed on its lower surface extending into said first bore, athird bore, a first keyway formed in its upper surface diametricallythereacross, and a threaded peripheral surface, a pin disposed in saidsecond and third bores to locate said first disc-shaped member relativesaid base, a second disc-shaped member having an upper surface and alower surface, a first key formed on its lower surface extendingdiametrically thereof and slidably disposed in said first keyway, and asecond keyway formed in its upper surface perpendicular to said firstkey and first keyway to provide first and second coordinate axes, athird disc-shaped member having an upper surface and a lower surface, asecond key formed diametrically across its lower surface and slidablydisposed in said second keyway, and a first conically shaped surface,means mounted on said third disc-shaped member for holding a formedelement, the element being thereby movable toward the corresponding formin any direction as provided by said coordinate axes, and a ring-shapednut including an inner threaded surface portion rotatably engaging saidthreaded peripheral surface of said first disc-shaped member, a secondconically shaped inner surface portion parallel to said first conicallyshaped surface of said third disc-shaped member, and an outer surfacecarrying spaced-apart indicia thereon corresponding to predeterminedtolerance settings for rotation of said ring-shaped nut, said parallelsurfaces parting an mount corresponding to a selected tolerance uponrotary setting of said nut and said second conically shaped innersurface portion defining the limits of movement of said second and thirddisc-shaped members within a selected tolerance.
 19. Apparatus accordingto claim 18, comprising a ring circumferentially surrounding and fixedto said ring-shaped nut including at least one detent therein defining azero tolerance setting of said apparatus, and said base means includinga spring loaded detent shaft for indexing said ring-shaped nut to thezero tolerance setting.